Robin Williams' wife Susan Schneider says in a statement that her husband had been suffering from early stage Parkinson's disease.

"Robin's sobriety was intact and he was brave as he struggled with his own battles of depression, anxiety as well as early stages of Parkinson's Disease, which he was not yet ready to share publicly," Schneider said in the statement.

Michael J. Fox, who has the disease and has been a vocal advocate for research, tweeted his own surprise at the revelation late Thursday:

“Robin spent so much of his life helping others. Whether he was entertaining millions on stage, film or television, our troops on the frontlines, or comforting a sick child — Robin wanted us to laugh and to feel less afraid.

"Since his passing, all of us who loved Robin have found some solace in the tremendous outpouring of affection and admiration for him from the millions of people whose lives he touched. His greatest legacy, besides his three children, is the joy and happiness he offered to others, particularly to those fighting personal battles.

"Robin's sobriety was intact and he was brave as he struggled with his own battles of depression, anxiety as well as early stages of Parkinson's Disease, which he was not yet ready to share publicly.

"It is our hope in the wake of Robin’s tragic passing, that others will find the strength to seek the care and support they need to treat whatever battles they are facing so they may feel less afraid.”

Previously: A day after Robin Williams died in an apparent suicide, the legendary comedian and actor's friends, colleagues and countless fans were left only with memories, heartache and questions.

Williams died from an apparent suicide by hanging at his home, the Marin County Sheriff's Department's Assistant Deputy Chief Coroner Keith Boyd said at a Tuesday press conference. He was found suspended with a belt around his neck wedged between the closet door and the door frame, Boyd said. He also had what were described as superficial wounds on the inside of his left wrist, with a pocket knife located nearby with what appeared to be blood on it.

Williams was last seen alive by his wife at approximately 10:30 p.m. on Sunday night, according to Boyd, but it's unknown when he went to bed. His wife left their home at 10:30 a.m., Boyd said. Robin Williams' personal assistant became concerned when he didn't answer the door according to Boyd, and the assistant managed to get into the room and found Williams having hanged himself.

The assistant called 911 at 11:55 a.m. and emergency personnel arrived on scene at 12 p.m., Boyd said, with Williams ruled dead at 12:02 p.m. A forensic investigation of Williams' body was conducted Tuesday morning, but the investigation is ongoing, Boyd said. Toxicology results will take two to six weeks, Boyd said.

"I would like to extend the condolences of the sheriff's office to the Williams family," Boyd said. "Mr. Williams had been seeking treatment for depression."

Boyd wouldn't discuss whether this was Williams' first suicide attempt or if there was a note.

Late-night talk show host Conan O'Brien received the news in the middle of taping Monday's episode. O'Brien, along with guests Will Arnett and Andy Richter, all of whom had worked with Williams in the past, took a moment to reflect:

Williams, known to friends as a sweet, kind soul, had long wrestled with addiction. The Associated Press provides a look back at that darker side:

Like many comedians, Williams often seemed driven by demons. He had a complicated personal life, suffered from depression and was treated for substance abuse, most recently earlier this summer. He did a few lines of cocaine with John Belushi on the last night of that comic's life.

A darkness seeped in during an interview with comedian Marc Maron in 2010, where Williams seemingly dismissed what would be a career highlight for many actors. "People say you're an Academy Award winner," he said. "The Academy Award lasted about a week and then one week later, people went, 'Hey Mork!'"

You can listen to Williams' full interview with Marc Maron below:

Remembering Robin Williams

Many who knew and worked with Williams remembered him as a brilliant improv comedian and a generous friend.

KPCC's Sanden Totten put together this audio tribute to Williams from KPCC callers:

“My family has always been private about our time spent together. It was our way of keeping one thing that was ours, with a man we shared with an entire world. But now that’s gone, and I feel stripped bare. My last day with him was his birthday, and I will be forever grateful that my brothers and I got to spend that time alone with him, sharing gifts and laughter. He was always warm, even in his darkest moments. While I’ll never, ever understand how he could be loved so deeply and not find it in his heart to stay, there’s minor comfort in knowing our grief and loss, in some small way, is shared with millions. It doesn’t help the pain, but at least it’s a burden countless others now know we carry, and so many have offered to help lighten the load. Thank you for that.

"To those he touched who are sending kind words, know that one of his favorite things in the world was to make you all laugh. As for those who are sending negativity, know that some small, giggling part of him is sending a flock of pigeons to your house to poop on your car. Right after you’ve had it washed. After all, he loved to laugh too…

"Dad was, is and always will be one of the kindest, most generous, gentlest souls I’ve ever known, and while there are few things I know for certain right now, one of them is that not just my world, but the entire world is forever a little darker, less colorful and less full of laughter in his absence. We’ll just have to work twice as hard to fill it back up again.”

Robin Williams' other children also released statements. From his son Zak:

"Yesterday, I lost my father and a best friend and the world got a little grayer. I will carry his heart with me every day. I would ask those that loved him to remember him by being as gentle, kind, and generous as he would be. Seek to bring joy to the world as he sought."

From his son Cody:

“There are no words strong enough to describe the love and respect I have for my father. The world will never be the same without him. I will miss him and take him with me everywhere I go for the rest of my life, and will look forward, forever, to the moment when I get to see him again.”

His ex-wife and mother of his children Marsha Garces Williams also released a statement:

“My heart is split wide open and scattered over the planet with all of you. Please remember the gentle, loving, generous - and yes, brilliant and funny - man that was Robin Williams. My arms are wrapped around our children as we attempt to grapple with celebrating the man we love, while dealing with this immeasurable loss.”

Take Two has put together a montage of some of Williams' great performances:

This is without question, the hardest few words I have ever tried to write. My life is a better place because I knew Robin Williams. To my children he was “Uncle Robin,” to everyone he worked with, he was the best boss anyone had ever known, and to me he was not just an inspiration but he was the Father I had always dreamed of having. There are not enough adjectives to describe the light he was, to anyone that ever had the pleasure to meet him. I will miss him everyday, but I know the memory of him will live on. And to his family, I thank them for letting us know him and seeing the joy they brought him.

Us Crazy Ones love you.

God, grant me the serenity to accept the things I cannot change, the courage to change the things I can, and the wisdom to know the difference.

Shawn Levy, who directed Williams in "Night at the Museum," had this to say:

I am shattered by the loss of my friend and collaborator Robin Williams. Onscreen and off, this was a formidable, incredible guy--generous in the best way: with his heart and humor, devoted to making others happy. Over his remarkable career, Robin moved us to tears; sometimes from laughter, sometimes from humanity, sometimes both in the same moment, a feat that few performers have equaled. I will miss Robin deeply but I will never stop treasuring the phenomenal, enduring work he gave to us all. Robin Williams was that rarest of things: a true and forever one of a kind.

The film's co-writer, Thomas Lennon, told KPCC in a statement, "I am devastated by the loss of my comedy hero, and I wish I could repay him for all the laughter he's given me."

Comedian David Steinberg:

Robin Williams and I went on stage together for six months last year playing theaters across the country. Besides seeing his brilliant improvisational mind in action every night was the pleasure in just getting to know him and his generosity and spirit.

He looked after Jonathan Winters and put him on his TV shows. He would drive to Santa Barbara weekly to make sure Jonathan was ok.

A comic genius looking after another comic genius. Robin looked after everyone. If only he would have looked after himself.

Garry Marshall, writer on the comedy series that presented one of Williams' earliest and best known roles — "Mork and Mindy" — shared several thoughts:

Once, years ago, Robin and I were walking on the Paramount lot near the set of our show “Mork and Mindy.” It was very late at night and we were talking and walking. Robin loved to stay up late and always had more energy than any person anywhere, in any room. I said to him that night, “Do you think we will ever grow up?” And he said without missing a beat, “I’m afraid if I ever grow up, I won’t be able to make a living.” Play was his passion and what drove him each day.

I will never forget the day I met him and he stood on his head in my office chair and pretended to drink a glass of water using his finger like a straw. The first season of “Mork and Mindy” I knew immediately that a three-camera format would not be enough to capture Robin and his genius talent. So I hired a fourth camera operator and he just followed Robin. Only Robin. Looking back, four cameras weren’t enough. I should have hired a fifth camera to follow him too.

Robin was hands-down a comedy genius and one of the most talented performers I have ever worked with in television or film. To lose him so young at the age of 63 is just a tragedy. I will forever be in awe of his timing, his talent and his pure and golden creativity. He could make everybody happy, but himself. He was my friend and it is rare that you ever have a friend that is also a genius.

Tom Shadyac, who directed Williams in "Patch Adams," recalled how much the actor embodied the character in that film:

"I think some of these things are divinely appointed, and the second I read the script — I had just finished the film 'Liar Liar.' I read the script when I was going on a quick vacation, and there was only one person that came to mind — Robin. And if Robin wasn't going to do the movie, I wasn't going to do the movie. He literally is Patch Adams. We toured a San Francisco hospital the first time I met him, when we were still talking about the role. And it was the role. He walked down the hallway, would disappear into rooms. Kids would be laughing. He'd be using instruments, improvisation. He just had such a huge heart and I know — you know, it's hard to talk about, but I know that huge heart also had huge pain. And it's the bipolarity of what we do in the arts. And he was just such a bright light, and that's why I felt it was important to talk to you and share that light today."

Shadyac said in an interview with KPCC's Nick Roman that the secret to letting that light shine through on screen was simple:

"Well, it's very easy with someone like Robin, because you let him know that you love him — literally, you love them, and that he is allowed to be fully himself. It didn't take me but a second to fall in love with Mr. Williams."

Shadyac said his heart broke when he heard the news of the actor's death: "I turned the news on and I just felt the light go out of the world, really. We'll miss him. And I think to honor him, we can just maybe be a little more of that light ourselves."

Not all of the reactions were stated eloquently, with some who appeared to disrespect Williams receiving negative reactions. Fox News's Shepard Smith, while covering Williams' death used the word "coward" to describe what Williams had done, which he later apologized for.

"To the core of my being, I regret it," Smith told Mediaite. "It just came out of my mouth. And I’m so sorry. And to anyone and their families who see that, I am sorry."

Minnesota Republican Party deputy chair Chris Fields received negative reaction for calling sadness over the death of Williams "how very 80's" and then urging voting for a Republican candidate to bring back the '80s Reagan economy, Raw Story reports.

At Williams' star on the Hollywood Walk of Fame, many people have gathered to pay respects and leave flowers and other mementos.

Monteith said she was in Los Angeles to become an actor and remembered being inspired by his performance in "Mrs. Doubtfire." She said she thought, "Wow, if I can be a fraction as invested and incredible as this, then that's the life for me."

Angeleno Miguel Lopez said Williams was his favorite comedian and that when he heard the news of his death, he picked up pen and paper and drew him the way he remembered him when he saw him in person for the first time.

Christopher Mulrooney, a veteran of the Iraq War, recalled Williams doing a USO show just days after former Iraqi leader Saddam Hussein's capture in 2003. After Mulrooney was positioned to guard the stage, a passing moment became a vivid memory:

All the sudden this arm came around me, startled me. I turned around. It was Robin Williams. And I said, "Sorry, Mr. Williams."

He goes, "Oh, note to self, do not startle soldiers on guard duty."

I said, "Well no, I'm a big fan."

He goes, "Well, I'd hate to be on the other side of the barrel if you weren't."

And he said, "Actually, you don't look too big to me, you could actually pass as my son."

And I said, "Well, hey Dad, where's my allowance?"

And then it goes on, then says, "Well, how old are you now son?" At the time I was 24.

He goes, "Well, you have to do 24 years of chores before you can talk to me about allowance."

I said, "Well don't get me started on the child support you would owe."

And he's like, "Whoa, whoa, that would be a lot."

So we joked on about five minutes after our meeting there, and then we went into the chow hall later on. And he came in, I said "Hey, Dad! I saved you a seat."

And all the soldiers looked at me, looked at my name tag, and "Wait, your name's Mulrooney, not Williams."

I said, "Well, haven't you ever heard of stage names?'

So they all believed us for about a half hour in the chow hall that we were father and son.

Mulrooney said that despite the discussion over the way Williams died, people should "remember all the good stuff he's brought, all the humor he's brought to everybody in this world. And he did that for us in a time when we were going to be the most depressed — around the holidays. And he brought us humor and cheer. For that moment, we weren't in Iraq. We were at a stage watching a really cool show with Robin Williams."

Some Williams fans reacted by turning the bench from "Good Will Hunting" into a makeshift tribute.

Rudy Garcia-Tolson, a two-time Paralympic Gold Medalist Swimmer for Team USA, remembers meeting Williams at the Malibu Triathlon when Garcia-Tolson was only 8 years old.

"Not too many people know, but Mr. Robin was actually a really big cyclist," Garcia-Tolson, who's now 25, told Take Two. "He used to actually go out to the Tour de France to watch the race, just because he loved the sport." From Take Two:

It was that passion for riding, Garcia-Tolson said, that helped spark his longtime friendship with the entertainer. They came together during the San Diego triathlon challenge as part of "Team Braveheart." Garcia-Tolson, at 9 years old, swam the 1.2-mile part of the journey. Williams handled the 56-mile bike ride, and Scott Findlay, an Ironman vet, took care of the running.